A Level 3 amber Government health warning was issued - one tier below a level 4 national emergency - as community groups ‘activated community emergency plans,’ and health staff were ordered to contact the ill and elderly, Government heatwave guidance said.

Hundreds of heatwave deaths are feared. 2,139 Brits died due to August 2003’s record 38.5C heatwave, 680 additional deaths were recorded in July 2006 amid 36.5C highs, and 300 extra Brits were killed in July 2009 amid 32C highs, Department of Health records show.

A man takes a break in Blackpool (Image: REUTERS)

Llangorse lake in Powys (Image: Daily Mirror/Rowan Griffiths)

The Met Office warning said: "There could be some flooding of homes, businesses and transport networks. Disruption to power is also possible."